148 



POACEAE 



27. CINNA L. Sp. PI. 5. 1753. 



Spikelets 1-flowered, disarticulating below the glumes, the rachilla forming a stipe 

 below the floret and produced behind the palea as a minute bristle ; glumes equal, 1- 

 nerved; lemma similar to the glumes, nearly as long, 3-nerved, short-awned just below the 

 tip; palea apparently 1-nerved, 1-keeled. Tall perennial grasses with flat blades and 

 paniculate inflorescence. [A Greek name for a kind of grass.] 



Species 3, North America and northern Eurasia, two in> the United States and one in Me.xico and Central 

 America. Type species, Cinna arundinacca L. 



1. Cinna latifolia (Trevir.) Griseb. 

 Slender Wood or Sweet Reed-g'rass. Fig. 327. 



Agrostis latifolia Trevir.; Goepp. Beschr. Bot. Gaertn. in 

 Breslau 82. 1830. 



Cinna pcndula Trin. Mem. Acad. St. Petersb. VI. Sci. Nat. 

 4': 280. 1841. 



Cinna latifolia Griseb. in Ledeb. Fl. Ross. 4: 435. 1853. 



Cinna arundinacca pcndula A. Gray, Man. ed. 2. 545. 1856. 



Cinna bolandcri Scribn. Proc. Acad. Phila. 1884: 290. 18S4. 



Culms .5-1.5 meters tall; blades 10-14 mm. wide; 

 panicle 15-30 cm. long, the flexuous capillary 

 branches spreading or drooping; glumes about equal. 

 scabrous, 4 mm. long; lemma about equaling the 

 glumes ; palea 2-nerved, the nerves close together. 



In moist places in woods and along streams. Transition 

 and Canadian Zones; in the cooler regions of North America 

 and Eurasia, extending south in the mountains to Sequoia 

 National Park, to Colorado and to North Carolina. July- 

 Aug. Type locality, European. 



28. AGROSTIS L. Sp. PI. 61. 1753. 



Spikelets 1-flowercd, disarticulating above the glumes, the rachilla usually not pro- 

 longed; glumes equal or nearly so, acute, acuminate, or sometimes awn-pointed, carinate, 

 usually scabrous on the keel and sometimes on the back; lemma obtuse, usually shorter 

 than the glumes, thinner in texture than these, awnless or dorsally awned, often hairy at 

 base ; palea usually shorter than the lemma, rarely 2-keeled, usually small and nerveless or 

 obsolete. Annual or usually perennial delicate or rather tall grasses with glabrous culms, 

 flat or sometimes involute, scabrous blades and open or contracted panicles of small 

 spikelets. [A Greek name for a forage grass.] 



Species about 100 in the temperate and cold regions of the world, especially in the northern hemisphere. 

 Type. species, Agrostis stolonifcra L. 



Lemma pubescent. 1. A. rctrofracta. 



Lemma glabrous. 



Kachilla prolonged behind the palea. 



Spikelets 3 mm. long, usually purple. 2. A. acquiialvis. 



Spikelets 2 mm. long, usually pale. 3. A. thurbcriana. 



Rachilla not prolonged. 



Palea evident, 2-nerved. 



Panicle contracted and lobed or verticillate; glumes scabrous on keel and back. 



4. A. verticillata. 

 Panicle open or if contracted not lobed or verticillate; glumes smooth on the back, more or less 

 scabrous on the keel. 

 Plant tufted; a dwarf alpine species. 5. A. humilis. 



Plant with rhizomes or stolons; tall species of lower altitudes. 



Panicles spreading; culms erect or somewhat decumbent at base, with rhizomes but with no 

 conspicuous stolons. 6. A. pahtstris. 



Panicles narrow, contracted; culms long-decumbent or producing from base conspicuous 

 stolons. 7. A. maritima. 



Palea wanting, or a small nerveless scale. 



Lemma provided with a slender awn about 5 mm. long; a delicate annual. S. A. c.vigua. 

 Lemma awnless or short-awned; perennials. 



Plants spreading by rhizomes (see also A. lepida). 



Tuft of hairs at base of lemma 1-2 mm. long. 9. A. hallii. 



